Lewis f



(No Model.)

L. F. GRISWOLD. EXTENSION DEVICE EUR LAME FIXTURES.

No. 420,875. Patented Feb. 4. 1890.

u W O Sintes `nrmvr .,Omricn.

LEI/VIS F. GRISWVOLD, OF MERIDEN, CONNECTICUT, ASSIGNOR TO THE vCHARLES PARKER COMPANY, OF SAME PLACE.

EXTENSION DEVICE FOR LAMP-FIXTURES.

SPECIFICATION forming part of Letters Patent No. 420,875, dated February 4, 1890.

Application filed May 3l, 1889. Serial No. 312,737. (No model.)

` To aZZ whom it may concern:

' Lamps; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this application.

My invention relates to a novel construction of what are known as extension devices, employed extensivelyin the construction of distensible lamp and gas fixtures, of either that type in which the lamp is suspended from the ceiling and adapted to be set at different elevations or that type in which the lamp is supported upon a pedestal or stand and adapted to be raised and lowered, as occasion or convenience may require.

In the drawings hereto annexed, and forming a part of this. specification, I have shown my invention applied to that type of adjustable lamp-fixtures known usually as a pianolamp, in which the lamp is supported upon `a pedestal composed usually of telescopic tubes, and is adapted to be raised and lowscopic pendant.

ered and held at any desired elevation, al`

though my said invention may, under proper modifications, be applied with perhaps equal advantage to that other type of known lixtures in which the lamp is suspended from the ceiling through the medium of a tele Previous tol my invention various devices have been contrived designed for the purpose of and operating to effectuatean adjustment of the lamp to any desired elevation, in some of which the proper engagement be tween the sliding tubes or an interlocking of one with the other has been effected through the medium of some positively-lookin g device which had to be manipulated by the person adjusting the fixture, and in others of which a frictional engaging device has been employed to effect the interlocking of the tubes against the tendency either of gravity or the suspension-spring, such frictional engaging device being thrown into and out of opera: tion automatically simply by the relative tubes of the fixture.

My improvement relates to the last-mentioned type or species of extension devices, in which a frictional engaging device for maintaining the tubes in any required relative position is employed-*that is, thrown into and movement or adjustment of the .telescopicl practiced it, although the novel principle of v construction and mode of operation peculiar to my vinvention 'may of course be carried into effect under various modifications.

In the drawings, Figure l is a sectional elevation of a piano-lamp embracing my invention and having certain portions of the stand or tubular pedestal cut away and the remaining portions moved toward each other for the purpose of condensing the drawing within the requisite limits vwithout having the scale too small to intelligibly illustrate the working parts. Fig; 2 isa duplication of a portion of the devices seen at Fig. l, and with some of the parts shown differently adjusted. Fig. 3 is a transverse view of the same parts shown in Fig. 2.

In the several figures the same part will.

everywhere be found designated by the same reference-letter.

A is the usual outer tube or cylindrical casing of the pedestal portion of the lampfixture, which is mounted upon or sustained by a stand or suitable supporting legs and frame A2, which may be of the design shown or of any other desirable pattern.

Within the outer stationary' tube A is arranged or located, in substantially the usual manner, the inner and adj ust-able lamp-supporting tube B, which is adapted to slide ver- TOO tic-ally within the outer tube A, and on the upper end of which is supposed to be arranged any desired form of lamp. The tube A is preferably closed at its upper end by means of a perforated disk P, within the central circular opening of which slides and lits the tube B, an ornamental cap-piece b2 being arranged, as shown, to cover the perforated disk P and make a finish at the jointure of the upper end of the stationary tube with the body of the sliding tube, while the lower end of said sliding tub'e is provided, as shown, with a disk-like head a2, the central portion of which is securely fastened to the lower portion of said tube B, and the perimeter of which iits and works within the bore of the outer tube or casing A, all as clearly shown. This disk-llke head a2 is formed or provided with depending ear-pieces c c', of a construction and for a purpose to be presently explained.

\Vithin the outer casing or tube A, and (in the case shown) between the interior wall thereof and the exterior surface of the sliding tube B, is arranged a rope or cable I, the upper end of which is permanently secured to the perforated disk P, and the lower end of which is fastened to the `upwardly-projecting lug or ear-like portion 7L of an adjustable disk or piece J, the downwardly-projecting stem from which passes through and works within the central aperture of a stationary disk or bar H, said steril terminating.,r in a screw-threaded rod k, the lower portion of which passes downwardly through the bottom plate or portion G et' the lamp-stand, and is provided, as shown, with a thumb-nut m, all in a manner and for a purpose to be presently explained. This rope or cable makesa turn around a spool or small drumf, which is mounted, as shown, *on a spindle e, the journal-like ends of which are arranged and work within oblong or slotted bearings (Z, that are formed in the pendent ears c c', hereinbefore mentioned, and said drum or spool f, around which the cable I thus makes a turn, is formed or provided at one end with a notched or toothed circular flange g, which is adapted to be thrown into and out of engagement with a stationary tooth or lug-like projection S on the inner face of the car-like de pending portion c'.

The operation. of the parts or devices so far described and shown in the drawings is about as follows: Supposing the parts to be in the relative position shown at Fig. l, (which shows the relationship in which the parts appear when the lamp mounted on the upper end of the supporting-tube Bis being elevated,) as soon as the lamp may be released from the hand of the person manipulating it, its gravity, combined with the weight of the movable tube B and its attachments, will cause the said tube to slightly descend until the projecting lug or tooth s shall have descended into engagement with one of the notches in trie periphery of the ilangegof the spool or drum f, which engagement of said tooth with said notched flange will of course prevent any rotation of the spool or drum f upon its axle or spindle c. Now as the rope or cable l, which makes a turn around this spool f, is supposed to be drawn and held sufficiently taut to exciteenough friction between itself andthe spool f, around which it passes, to prevent any slip of said cable upon the periphery of said spool by the action of gravity of the lamp and its supporting-tube B, said lamp will of course remain in substantially the position in which it was left when released from the hand of theperson manipulating it. If, however, it should be desirable to lower the lamp, this degree of friction between the cable and the periphery of the spool f will be insuilicicnt to overcome a slight pressure applied to the movable parts, operating in addition to the gravity of said parts and tending to force the lamp downward to any desired elevation. If it be dcsired, on the other hand, to elevate the lamp, the initial upward movement of the lamp, which may be eifected by hand, will operate to disengage the lug s from the teeth of the eircular ilange g, and the spool or drum f then being left free to rotate on its axis or spindle e, the lifting of the lamp and its pendent tube B will encounter little or no obstacle from the action of the cord or cable I, since then the spool f will simply roll along, so to speak, upwardly, unwinding in one direction and winding up in the other direction that portion of t-he cable which makes the turn around the periphery of said spool, and Whenever the lamp shall have been elevated to the requisite point in this manner a releasement of it by the hand of the person will permit an almost imperceptible descent of the lamp until the lug s shall have become re-engaged with one of the notches of the flange g,where upon the spool f will be again locked against any rotatory movement, and the frictional action of the cable upon the periphery of the spool again created to effect the retention of the adjustable parts in the position to which they may have been moved.

It will be seen that by reason of the spindle e of the spool fworking within the slotted or oblong bearings or apertures d of the depending ears c c the mode of operation just explained is made possible, and it will also be seen that under this mode of operation, while no practical impedimentis offered to the upward movement of the lamp audits permanent attachments, (during which movement the gravity of the lamp` of course has to be overcome by the person manipulating it,) the frictional locking device exerts suliicient force or impediment to any downward movement of the lamp to prevent any auto` matic or casual descent of the moving parts, while at the same time such parts may be easily forced downward to any desired ere ICO IIO

taining the proper degree of friction between the periphery of the spool f and that portion of the cable which makesa turn around said spool, and for the purpose also of varying the operation of these part-s to suit lamps of different weights, which may be applied to the movable tube B, I provide the simple means shown at the lower end of the outer tube A for exerting a draft-strain on the cable I and for drawing it and holding it more or less taut, as circumstances may require, said contrivance consisting, as shown and already briefly described, in the sliding pull-bar or disk J, which is drawn downwardly to any desired extent and held in adjustment through the medium of the thumb-nut m, acting upon the threaded stem k, all in a manner to be easily understood by those skilled in the art. Of coursenot only may this adjusting device or contrivance be varied in the details of its construction, but some other means or device may be applied in a somewhat different manner, if deemed expedient, for the purpose of exerting more or less draft-strain on the cable, in order that the turn thereof around the periphery of the spool f may be made to bind said spool with more or less frictional force, as circumstances may require, for the purpose of rendering the frictional locking device capable of acting with more or less force.

I, however, consider it an important feature of my improved extension device that the thumb-nut (or whatever other device may be used in lieu thereof) be located exteriorly of the telescopic tubes, so as to constitute a perfectly-accessible means for setting or adjusting the friction lock or brake so as to act with different degrees of force, according to the variableness ofI the gravity of different lamps or articles to be held in suspension by the extension device.

In lieu of the precise detail construction shown with reference to the frictional and automatically operating engaging device, modiiications in the detail construction may of course be made without departing from the pith or essence of the main feature of my invention, which consists, essentially, in a friction-lock or engaging device which is ar ranged interiorly of the stem or pedestal ot' the lampstand, is carried by the inner end of the interior tube, which is automatically thrown out of action whenever the lamp may be raised, and which automatically comes into an operative condition whenever the lamp maybe allowed to descend or come to a state of rest by its own gravity, and is adjustable from without the exterior tube.

Of course, in'either substantially the form shown or under one or another modification, my invention may be applied with more or less advantage to that other type of extension devices for lamp-fixtures, ac., in which the stationary tube depends from an elevated point of support, and in which the lamp or other article to be raised or lowered is applied to the lower end of the sliding tube.

Having now so fully explained the nature and operation of my improved contrivance that those skilled in the art can make and use my invention, either in the form shown and described or under some modification of such form, what I claim as new, and desire to secure by Letters Patent, is-

I. In combination with the stationary-and sliding parts of an extension device, a spool or drum movably lconnected with one of said parts, a bindingl cord or cable which makes one or more turns around the periphery of s aid spool and has its ends securedor attached to the other one of said parts, and means by which said spool or drum is rendered non rotative whenever the movable part of the extension device is acted upon by the gravity of the lamp, all substantially in the manner and for the purposes hereinbefore set forth.

2. In combination with the movable and stationary tubes, a drum or spool having its spindle in engagement with one of said parts, 95 and a cable secured to the other of said parts and partially wound around said spool or drum, means for increasing or diminishing the degree of tantness of said cable for the purpose of increasing or diminishing its'fricroo tional action on said spool or drum, in substantially the manner and for the purposes hereinbefore set forth.

3. In combination with the two telescopic ally-arranged tubes and a friction-lock lo- 1o 5 cated within the outer tube and carried by the inner end of the interior tube, means for adjusting or setting the said friction-lock to act with different degrees of brake-power,

having a protruding portion accessible exterio riorly of the outer tube for the purposes of conveniently manipulating the said adjusting device, all substantially in the manner and for the purposes hereinbefore set forth.

In witness whereof I have hereunto set my hand this 6th day of May, 1889.

LEWIS F. GRISXVOLD. In presence of-'- W. H. LYON, W. T. RIGHTMYER. 

